Grid bars conforming to this type and screens that are thus equipped are known in the prior art and are used, for example, for the removal of coarse screening material from wastewater flowing in a sewer channel. For this purpose, the screen grid comprising grid bars is integrated in the sewer channel in such a manner that the screen surface formed by the grid bars, starting from a channel bottom of the sewer channel, extend in a direction that is vertical or slightly tilted upward. Finally, for removing the screening material retained by the screen grid, one or more cleaning elements may be present, which may be moved with the assistance of a drive relative to the screen grid, in order to remove the screening material from the screen grid.
In order to ensure the necessary strength and bending stiffness of the individual grid bars, the known grid bars are manufactured from a metal, for example stainless steel. Therefore, the production of the grid bars is correspondingly cost-intensive.